<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button id="btn">点击发送ajax</button>
    <script>
        let api = 'https://api.mcloc.cn/love'
        const btn = document.querySelector('#btn')
        btn.addEventListener('click', function(){
            const p = new Promise((resolve, reject)=>{
                // 1.创建对象
                const xhr = new XMLHttpRequest()

                // 2.初始化
                xhr.open('GET', api)

                // 3.发送
                xhr.send()

                // 4.处理响应结果
                xhr.onreadystatechange = function () {
                    if(xhr.readyState === 4) {
                        if(xhr.status >=200 && xhr.status < 300) {
                            resolve(xhr.response)
                        } else {
                            reject(xhr.status)
                        }
                    }
                }
            })
            
            p.then(value=>{
                console.log(value)
            }, reason=>{
                console.log(reason)
            })

        })
    </script>
</body>
</html>